Heat transfer system for warehoused goods

ABSTRACT

A high efficiency airflow management system can be used to reliably and consistently draw air through palletized product stacks with a minimum of energy expenditure. A racking system is provided with a grid of pallet bays separated from an air plenum/chamber by a wall having an airflow opening for each pallet bays. An air seal is formed at the periphery of each opening by resiliently flexible side seals and a top seal to form a highly airtight interface between the pallet assembly and the adjacent airflow opening. When a pressure differential is developed between the chamber and the pallet bay, air is efficiently drawn substantially exclusively through the pallet assemblies with minimal leakage. The flexible sealing arrangement accommodates pallet assemblies with unevenly stacked rows of cases without significant loss of system efficiency.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under Title 35, U.S.C. § 119(e) ofU.S. Provisional Patent Application Ser. No. 62/235,030, entitled HEATTRANSFER SYSTEM FOR WAREHOUSED GOODS and filed on Sep. 30, 2015, theentire disclosure of which is hereby expressly incorporated by referenceherein.

BACKGROUND 1. Technical Field

The present disclosure relates to a warehouse that is capable ofaltering and/or holding steady the temperature of a quantity of producthoused in cases forming pallet assemblies and storing such product,e.g., bulk foods. More particularly, the present disclosure relates tospacing, stacking and heat transfer structures used in such a warehouse.

2. Description of the Related Art

Freezer warehouses are known in which large pallets of items includingmeats, fruit, vegetables, prepared foods, and the like are frozen inblast rooms of a warehouse and then are moved to a storage part of thewarehouse to be maintained at a frozen temperature until their removal.

U.S. Pat. No. 8,783,047 entitled “Rack-Aisle Freezing System forPalletized Product”, filed on Sep. 8, 2010, the entire disclosure ofwhich is hereby explicitly incorporated by reference herein, relates toan improved system for freezing food products. Shown in FIG. 1 is alarge warehouse 2 that can be used to freeze and maintain perishablefoods or like products. Large pallets of items, including meats, fruits,vegetables, prepared foods, and the like, are sent to warehouse 2 to befrozen employing a system whereby the palletized foods are frozen onstorage racks.

FIG. 2 shows a top view of the interior of warehouse 2, in which rows ofpalletized product are shown such that pallet assemblies 52 abut chamber6. As shown in FIG. 3, rows of racking 14 (see also FIG. 8) arepositioned between aisles 10 and chambers 6. Each chamber 6 is enclosedby a pair of end walls 15 and top panel 17. Spacers 20 (FIGS. 5-7)separate respective rows of cases 22 to create a palletized productstack in the form of pallet assembly 52 which can be disposed and sealedagainst the exterior of racking 14 (FIG. 3) via forklifts 18 (see, e.g.,FIGS. 3 and 4).

Air handlers 8, e.g., chillers or heaters (FIG. 2) provided in theinterior of warehouse 2 produce conditioned, e.g., cold or warmed airand maintain the temperature of ambient air within the warehouse spaceat a desired temperature, e.g., +55° F. to −30° F. Thus, for purposes ofthe present disclosure, “air conditioner” refers to an air handler whichcan produce air conditioned to a desired state, e.g., heated or cooled.While warehouse 2 could be utilized to either freeze, cool or thaw aquantity of product housed in cases contained on pallet assemblies 52,the remaining description will use the example of a warehouse freezer,it being understood that similar arrangements and principles will beapplied to a warehouse utilized to thaw product, with the air handlercomprising a heater as opposed to a chiller.

Adjacent pairs of racking structures 14 (FIGS. 2-4) define a pluralityof adjacent airflow chambers 6 (FIGS. 2 and 4) having air intakeopenings on opposite sides thereof and a plurality of air outlets havingair moving devices, such as exhaust fans 12, on top panels 17, whichcause conditioning air to be drawn into chambers 6 through the airintake openings in racking 14 and to then exhaust into the warehousespace. The plurality of airflow chambers 6 are each defined by a pair ofend walls 15 and top wall 17 having one or more air outlets and exhaustfans 12 associated therewith (FIG. 3). Pallet assemblies 52 (FIG. 5) arepressed against the intake openings in racking 14 such that a seal isformed between the pallets and the intake openings via side peripheryseals, a bottom periphery seal, and a top periphery seal. The sealstogether define each respective intake opening. Freezing air is drawnthrough air pathways 16 (FIGS. 2, 4, and 5) within the palletizedproduct in a direction towards chamber 6 to thereby quickly freeze theproduct. As shown in FIG. 5, spacers 20 may be placed between rows ofcases 22 of product in an attempt to provide air pathways 24 throughwhich airflow can enter chamber 6.

U.S. Pat. No. 8,919,142 entitled “Swing Seal for a Rack-Aisle Freezingand Chilling System”, filed on Mar. 29, 2011, the entire disclosure ofwhich is hereby explicitly incorporated by reference herein, discloses atop periphery seal useable to seal an intake opening as described aboveand which automatically adjusts to the height of pallet assembly 52 asillustrated in FIG. 6. As illustrated in FIG. 6, pallet assembly 52(comprised of a plurality of cases 22 stacked on spacers 20 and pallet4) can be positioned along pallet guide 56 and pressed against airflowopening 54 such that a seal is formed between pallet assembly 52 andairflow opening 54 via side periphery seals, a bottom periphery seal andan automatically adjustable top periphery seal surrounding airflowopening 54. With such a construction, chilling or freezing air is drawnthrough air pathways 16 formed through pallet assembly 52, asillustrated in FIGS. 2, 4 and 5.

FIG. 5 illustrates predicate spacer 20 which is formed in an undulating“egg carton” configuration. As illustrated in FIG. 7, individual cases22 can crush under the weight of the product contained therein and theproduct contained in cases stacked directly above to cause overlap ofcases 22 with a spacer 20 and prohibit airflow between product cases 22positioned on opposite sides of the obstructed spacer 20. Undulatingspacers 20 are particularly susceptible to obstruction due to droopingor sagging cases 22 due to the inconsistent support structure caused bythe “hill and valley” configuration of such spacers. FIG. 7 illustratescase crushing and drooping at various sides and levels of palletassembly 52; however, this phenomenon is, in practice, more prevalentlyseen with respect to the spacers 20 separating lower rows of cases 22,as the bottom of pallet assembly 52 contains the heaviest cumulativeload of cases 22 stacked thereon.

In the above described installation, utilizing “egg carton” spacers 20,heat transfer from chilled ambient air in warehouse 2 to the productscontained in cases 22 is effected through forced convection which isfacilitated by the irregular shape of egg carton spacers 20 to allowairflow in all directions through pallet assembly 52. Alternativespacers such as wood slat spacers may also be utilized to separate cases22 on pallet 4.

For maximum effectiveness of thermal transfer between the conditionedair in warehouse 2 and the product contained in product cases 22, it isdesirable to have air within the spacers continuously refreshed andreplaced with conditioned air from warehouse 2. One may to achieve thisair movement is to use fans 12 (FIGS. 3 and 4) to drive airflow throughand around pallet assemblies 52.

SUMMARY

The present disclosure provides a high efficiency airflow managementsystem which can be used to reliably and consistently draw air throughpalletized product stacks with a minimum of energy expenditure. Aracking system is provided with a grid of pallet bays separated from anair plenum/chamber by a wall having an airflow opening for each palletbays. An air seal is formed at the periphery of each opening byresiliently flexible side seals and a top seal to form a highly airtightinterface between the pallet assembly and the adjacent airflow opening.When a pressure differential is developed between the chamber and thepallet bay, air is efficiently drawn substantially exclusively throughthe pallet assemblies with minimal leakage. The flexible sealingarrangement accommodates pallet assemblies with unevenly stacked rows ofcases without significant loss of system efficiency.

In certain exemplary embodiments, the racking system may further includean air dam within the plenum which operates to compensate for a vacantbay by automatically closing some or the entire air flow opening uponremoval of the pallet assembly from the bay. For example, the air dammay take advantage of the increased air flow which results from removingthe pallet assembly from its seal configuration against the air flowopening to pivot or swivel an air dam to a shut position to preventsignificant draws of air through the vacant bay and into the plenum.This vacant bay compensation system cooperates with the tight air sealin occupied pallet bays to minimize the power required of the fansserving the plenum.

The disclosure, in one form thereof, provides an installation forwarehousing palletized product, comprising: a pallet racking assemblycomprising: a pallet receiving space sized and configured to receive apallet assembly including a pallet and a plurality of vertically stackedrows of cases disposed on the pallet and providing an airflow pathwaythrough the vertically stacked rows of cases; an airflow chamberincluding an air inlet and an air outlet; an air handler positioned todirect air into the airflow chamber from the air inlet and exhaust airfrom the airflow chamber through the air outlet; a wall disposed betweenthe pallet receiving space and the airflow chamber, the wall having atleast one airflow opening having a substantially planar openingperiphery defining an opening plane, the airflow opening sized andpositioned to be engaged by the pallet assembly when the pallet assemblyis pressed against the opening periphery; a first side seal and disposedalong a first side edge of the opening periphery, the first side sealdefining a resiliently deformable first seal surface extending from thefirst side edge into the pallet receiving space, such that the firstseal surface faces the pallet receiving space and defines a first obtuseangle with the opening plane; a second side seal and disposed along asecond side edge of the opening periphery, the second side seal defininga resiliently deformable second seal surface extending from the secondside edge into the pallet receiving space, such that the second sealsurface faces the pallet receiving space and defines a second obtuseangle with the opening plane.

The disclosure, in another form thereof, provides an installation forwarehousing pallets of product, comprising: a plurality of palletassemblies, each pallet assembly comprising: a pallet; a plurality ofvertically stacked rows of cases disposed on the pallet and providing anairflow pathway through the vertically stacked rows of cases containingthe product; and at least one spacer disposed between the plurality ofvertically stacked rows of cases, the spacer having a longitudinalairflow channel formed therethrough; and a pallet racking assemblycomprising: a plurality of pallet bays having the plurality of palletassemblies removably received therein; an airflow chamber including anair inlet and an air outlet; an air handler positioned to direct airinto the airflow chamber from the air inlet and exhaust air from theairflow chamber through the air outlet; a wall disposed between theplurality of pallet bays and the airflow chamber, the wall having anairflow opening in each of the plurality of pallet bays, each airflowopening having a substantially planar opening periphery defining anopening plane, the airflow opening sized and positioned to be engaged bythe pallet assembly when the pallet assembly is pressed against theopening periphery;

The disclosure, in a further form thereof, provides a method of sealingan airflow opening with a pallet assembly, the method comprising:advancing the pallet assembly into a pallet bay along a depth directionuntil the pallet assembly reaches a seat position adjacent the airflowopening; during the step of advancing the pallet assembly, engaging thepallet assembly with a resiliently flexible left side seal and aresiliently flexible right side seal disposed at the left and rightedges of the airflow opening respectively; during the step of engaging,deflecting the left side seal and the right side seal toward the airflowopening along the depth direction and away from the airflow openingalong a lateral direction, such that the left side seal and right sideseal conform to left and right vertical edges of the pallet assemblyrespectively; and during the step of advancing the pallet assembly,engaging the pallet assembly with a top seal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this disclosure,and the manner of attaining them, will become more apparent and thedisclosure itself will be better understood by reference to thefollowing description of embodiments of the disclosure taken inconjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a warehouse incorporating a heattransfer system in accordance with the present disclosure;

FIG. 2 is a diagrammatic top view of a heat transfer warehouseincorporating the system of the present disclosure;

FIG. 3 is a perspective view of the interior of the warehouseillustrated in FIG. 1;

FIG. 4 is a perspective, end view of two rows of racking separated by anairflow chamber;

FIG. 5 is a perspective view showing a desired airflow through a palletassembly;

FIG. 6 is a perspective view illustrating loading of pallet assembliesinto the racking illustrated, e.g., in FIGS. 3 and 4;

FIG. 7 is a perspective view of a pallet assembly incorporating apredicate spacer;

FIG. 8 is a perspective view of a portion of a racking structureaccommodating 24 pallet assemblies on each side thereof;

FIG. 9 is an end view of a pallet assembly in accordance with thepresent disclosure;

FIG. 10 is a perspective view of a multi-bay racking system includingresiliently flexible side seals in accordance with the presentdisclosure;

FIG. 11 is a perspective view of a portion of the racking system shownin FIG. 10, illustrating the placement of fans atop a plenum;

FIG. 12 is a perspective view of vacant bay in the racking system ofFIG. 10, showing two flexible side seals and a top swing seal;

FIG. 13 is a top plan view of a portion of the vacant bay shown in FIG.12, taken along the line XIII-XIII of FIG. 12, illustrating anundeflected side seal;

FIG. 14 is another top plan view of the side seal shown in FIG. 13, inwhich the side seal is deflected by a pallet assembly engaged therewith;

FIG. 15 is a top perspective view of a portion of the racking assemblyshown in FIG. 10, illustrating occupied and vacant bays;

FIG. 16 is an elevation view of a portion of the racking assembly shownin FIG. 10, taken from within the air plenum of the assembly, andillustrating engagement of unevenly stacked pallet cases with theresiliently flexible side seal;

FIG. 17A is a cross-section, elevation view of a top swing seal inaccordance with the present disclosure, taken along the line XVII-XVIIof FIG. 12, and illustrating an at-rest position of the swing seal;

FIG. 17B is another cross-section, elevation view of a top swing seal inaccordance with the present disclosure, taken along the line XVII-XVIIof FIG. 12, and illustrating an at-rest position of the swing seal;

FIG. 17C is a perspective view of a swing seal weight assembly inaccordance with the present disclosure;

FIG. 18 is a schematic, elevation view of a portion of the rackingassembly shown in FIG. 10, in which the pallet bay is occupied and anair dam disposed within the air plenum in a non-engaged configuration;and

FIG. 19 is another schematic, elevation view of the portion of theracking assembly shown in FIG. 18, in which the pallet bay is vacant andthe air dam has moved to its engaged configuration.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the exemplifications set outherein illustrate embodiments of the disclosure, in several forms, theembodiments disclosed below are not intended to be exhaustive or to beconstrued as limiting the scope of the disclosure to the precise formsdisclosed.

DETAILED DESCRIPTION

The present disclosure provides a system and method for efficientlydirecting air flow through pallet assemblies 52 with a minimum of energyexpenditure by the fans which drive such air flow. In particular, and asdescribed in further detail below, the present disclosure providesracking assembly 214 (FIG. 10) including an arrangement of resilientlyflexible side seals 260, 262 disposed along the side edges of an airflowopening 54. The side seals 260, 262 cooperate with either a swing seal40 or a top seal (not shown) to provide a substantially air tight sealbetween pallet assemblies 52 and the periphery of respective air flowopenings 54 (FIG. 15). This illustrated arrangement of seals, togetherwith the overall air tight structure of racking assembly 214, ensuresthat pressure differentials induced by fans 212 between chamber 6 andthe ambient warehouse environment will cause airflow exclusively throughthe intended pathways through and between cases 22 of pallet assemblies52 via airflow openings 54, without any significant “leakage” or“spillage” of air around pallet assemblies 52.

In addition, an arrangement of air dams 270 (FIGS. 18 and 19) may beprovided within or external to air chamber 6 and configured tosubstantially reduce or eliminate air flow through vacant bays 202 ofracking 214 when pallet assemblies are removed therefrom. By restrictingsuch vacant-bay air flow, the desired pressure differential betweenchamber 6 and the ambient air of warehouse 2 may be reliably maintainedwithout increasing the power requirements of fans 212.

1. Palletized Product Environment, Assembly and Arrangement.

Pallet assemblies 52 form a part of warehouse installation 2 depicted,e.g., in FIG. 2. The general structure and components of warehouse 2 aredescribed above in the background section of this document. A portion ofthis description will be repeated here to facilitate an understanding ofthe present invention. As illustrated in FIG. 2, warehouse 2 includesrack rows 26 separated by chambers 6 and aisles 10. As illustrated inFIGS. 3 and 4, racks 14 are sized for receiving a plurality of palletassemblies 52. Racking 14 can be sized to receive a different number ofpallet assemblies, as necessary. Different assemblies of racking 14 areillustrated, e.g., in FIGS. 3, 4, 8 and 10.

As depicted, e.g., in FIG. 9, pallet assemblies 52 include pallet 4, onwhich a plurality of cases 22 are stacked, with spacers 30 interposedbetween layers of cases 22. Spacers 30 are provided to facilitateairflow across the entire downstream extent of pallet assemblies 52,thereby ensuring heat transferring airflows to all of cases 22 among thevarious layers stacked upon pallets 4. Exemplary spacers and otherracking systems and structures which may be used in conjunction with thepresent disclosure are described in U.S. Patent Application PublicationNo. 2014/0273793, filed Jan. 28, 2014 and entitled HEAT TRANSFER SYSTEMFOR WAREHOUSED GOODS, and in U.S. Patent Application Publication No.2014/0273801, filed Mar. 15, 2013 and entitled SPACER FOR A WAREHOUSERACK-AISLE HEAT TRANSFER SYSTEM, the entire disclosures of which arehereby explicitly incorporated herein by reference.

With pallet assemblies 52 arranged in rows and columns on racks 14,warehouse installation 2 can be utilized to raise, lower and/or maintainthe temperature of a quantity of product contained in cases 22 to adesired set point. As illustrated in FIGS. 3 and 4, aisles 10 aresufficiently wide to allow forklifts 18 to access pallet assemblies 52.Typical aisle width is between 5 feet to 14 feet depending on the typeof lift equipment. Pallet assemblies 52 each include a pallet 4 at thebottom thereof. As used in this document, “pallet” is used to denote astandard warehouse pallet of box section open at least two ends (somepallets are called 4-way pallets due to fork openings on all 4-sides) toallow the entry of the forks of a forklift so that a palletized load,i.e., pallet assembly 52, can be raised, moved about and set downeasily.

Racks 14 define airflow openings 54 fluidly connected to a chamber 6,which, in the exemplary embodiment illustrated, is enclosed by a pair ofend walls 15 and top panel 17. Pallet assemblies 52 are disposed andsealed against the air intake openings formed in racks 14, as describedin detail below. Referring to FIG. 2, air handlers 8 are operablyconnected to (e.g., disposed within) warehouse space 2 so that airhandlers 8 can condition (e.g., heat or cool) the ambient air inwarehouse space to a desired temperature. In the event that warehousespace 2 is utilized to freeze product contained in cases 22, airhandlers 8 may be chillers which produce air on the order of −5° F. to−30° F. In the event that warehouse space 2 is utilized to thaw productcontained in cases 22, air handlers 8 may be heaters which produce airon the order of 30° F. to 60° F. Additional air handlers, illustrativelyfans 12, circulate ambient air conditioned by air handlers 8 such thatair conditioned by air handlers 8 flows through pallet assemblies 52 andthrough airflow openings 54 formed in racks 14.

In one exemplary embodiment, pallet 4 defines a standard 40 inch by 48inch rectangular outer perimeter. With such a pallet, first surface 32and second surface 34 of spacer 30 illustrated in FIG. 9 will both besubstantially rectangular in shape and about 40 inches by about 48inches. Stated another way, first surface 32 and second surface 34 areboth nominally rectangular and nominally measure about 40 inches by 48inches. In certain alternative embodiments, spacers 30 will be slightlyoversized with respect to pallet 4, e.g., by having an overhang of up toan inch relative to the perimeter of pallet 4. These embodiments arealso considered to be sized and shaped “about congruent” to the outerperimeter of pallet 4. Alternative pallet sizes, such as a standardEuropean pallet may be utilized. Spacers 30 may be about congruent withthe pallet and cases with which the spacers 30 are paired.

As illustrated in, e.g., FIG. 9, spacers 30 may have longitudinalairflow channels 38 formed therethrough. Airflow channels 38 facilitatea generally longitudinal, directional flow of air through the spacerfrom an input at one side of the palletized product assembly 52 to anoutput at an opposite side. Further discussion of exemplary longitudinalchannels and spacer arrangements can be found in U.S. Patent ApplicationPublication No. 2014/0273793, filed Jan. 28, 2014 and entitled HEATTRANSFER SYSTEM FOR WAREHOUSED GOODS, and in U.S. Patent ApplicationPublication No. 2014/0273801, filed Mar. 15, 2013 and entitled SPACERFOR A WAREHOUSE RACK-AISLE HEAT TRANSFER SYSTEM, the entire disclosuresof which are hereby explicitly incorporated herein by reference.Although spacers 30 provide enhanced airflow and heat transferperformance characteristics as compared to predicate spacers 20 and areused in an exemplary embodiment of pallet assembly 52, it iscontemplated that spacers 20 may also be used in pallet assembly 52together with racking 214 (described further below), as required ordesired for a particular application.

2. Racking Assembly and Pallet/Rack Interface.

Turning now to FIG. 10, racking assembly 214 is shown with palletreceiving spaces, hereinafter referred to as bays 202 arranged in sixrows of four bays. As described above, bays 202 of racking 214 may beprovided in any configuration of columns and rows, as may be required ordesired for a particular application, or may be provided with a singlebay 202 in some applications. In the illustrated embodiment of FIG. 10,various bays 202 are shown vacant, while other bays 202 include a palletassembly 52 received therein and sealingly engaged over airflow openings54.

As further described below, each bay 202 includes left side seal 260 andright side seal 262 which cooperate to prevent airflow around the sidesof pallet assemblies 52 during operation of the installation, e.g., viaair pathways 16 as shown in FIG. 5. Each bay 202 may also include a topseal, such as swing seal 40 disposed in the upper portion of eachairflow opening 54, which prevents airflow over the top of palletassembly 52.

As also described further below, each airflow opening 54 may have airdam 270 positioned behind opening 54 (FIGS. 18 and 19) and within airplenum or chamber 6 in order prevent large-volume flows of air throughairflow openings 54 when bays 202 are vacant. In an exemplaryembodiment, the illustrated arrangement of seals and air dams cooperateto provide a highly airtight interface between chamber 6 and bays 202,such that substantial air flows may be achieved substantiallyexclusively through pallet assemblies 52. This ensures that theelectrical power provided to fans 212 is used solely for its intendedpurpose of transferring heat to or away from the product in cases 22,and therefore enables the use of smaller and/or reduced-power fans ascompared to what would be required for a more “leaky” system. Suchreduced-power fans may be less expensive to purchase and maintain, andrequire minimal expenditure on electrical power for operation.

For purposes of the present disclosure, reference directions relative toracking assembly 214 are taken from the perspective of an operator ofracking assembly 214 facing bays 202 from within aisle 10 (FIG. 2).Thus, a “depth direction” is the direction of insertion or removal ofpallet assembly 52 into or out of a respective bay 202. The depthdirection is therefore the direction along which the depth dimension ofbays 202 is measured. Similarly, a “width direction” refers to atransverse direction perpendicular to the depth direction. The widthdirection is therefore the direction along which the width of bays 202is measured, with the width of an illustrated bay 202 being the shortestdistance between a pair of pallet guides 56. Finally, a “heightdirection” refers to a vertical direction perpendicular to both thedepth and width directions. The width direction is therefore thedirection along which the overall height of bays 202 is measured. In theillustrative embodiment of FIG. 13, opening plane P is defined byairflow openings 54 and extends along the width and height directionsand is perpendicular to the depth direction.

As best seen in FIGS. 11 and 15, pallet assembly 52 interacts with sideseals 260, 262 and swing seal 40 when received and seated within avacant bay 202. As noted above, pallet assembly 52 may include severallayers of stacked cases 22 on top of pallet 4, with airflow spacers 30disposed between respective layers. Assembly 52 is deposited into avacant bay 202 by passing pallet 4 into pallet guides 56 and advancingpallet assembly 52 along the depth direction into the bay 202 untilpallet 4 abuts pallet stop frame member 238. Pallet stop frame member238 is substantially flush with airflow opening 54, which in turndefines a substantially planar opening periphery defining opening planeP as shown in FIG. 13.

If the various cases 22 and spacers 30 of pallet assembly 52 are evenlystacked upon one another, cases 22 and spacers 30 may cooperate with theadjacent portions of wall 230 to form a marginal air seal in this “fullyseated” position of pallet assembly 52. This marginal seal may allow anacceptably low amount of air to flow around pallet assembly 52 and intoairflow opening 54, i.e., air pathways 16 (FIG. 5) may be acceptablylow.

However, as best seen in FIG. 16, some pallet assemblies may haveunevenly stacked cases 22 and/or spacers 30. Such uneven stacking mayresult from, e.g., shifting during transport, variable sizes among cases22, or imprecise stacking of cases 22 and/or spacers 30 duringpreparation of pallet assembly 52. When unevenly stacked in this way,substantial gaps may exist between respective cases 22 and/or spacersand the adjacent periphery of airflow opening 54 even when pallet 4 isfully seated against pallet stop frame member 238. Left side seal 260and right side seal 262 are disposed along respective side edges of theperiphery of airflow opening 54, as best seen in FIG. 12, minimize oreliminate airflow via pathways 16 (FIG. 5) arising from such unevenstacking arrangements, as further described below.

In an exemplary embodiment, side seals 260, 262 extend vertically fromthe base of airflow opening 54, illustrated as the top of pallet stopframe member 238 in FIG. 12, to the upper edge of the periphery ofopening 54. This full-height configuration ensures that the side sealswill be maintained regardless of the amount of rotation experienced byswing seal 40, which is dependent on the height of pallet assembly 52. Alower height of pallet assembly 52 results in relatively less rotationwhen assembly 52 is fully seated in bay 202 (see, e.g., FIG. 18), butfor a taller pallet assembly 52 (such as a pallet assembly 52 whichoccupies nearly the entire vertical height of pallet bay 202), swingseal 40 may rotate into chamber 6 by a substantial amount. In thistall-pallet configuration, the illustrated full-height side seals 260,262 can maintain an airtight side seal even if portions of swing seal 40rotate away from the periphery of opening 54. However, in someembodiments, it may be suitable to terminate side seals 260, 262 at alower height, including as low as the lower edge of swing seal 40.

In the illustrated embodiment, left side seal 260 and right side seal262 are mirror images of one another about a vertical plane bisectingbay 202 (i.e., a vertical plane extending in the depth direction).Accordingly, both side seals 260, 262 have the same structure andspatial arrangement with respect to the surrounding structures ofracking assembly 214, and a reference to left side seal 260 can be takenas a corresponding reference to right side seal 262.

Side seal 260 is made from a resiliently deformable material,illustratively from a series of substantially parallel resilientlydeformable fibers 264, as shown in FIG. 13. This type of seal iscommonly referred to a “brush seal” because the fibers 264 combine toform a brush-like appearance. Through the individual deformation offibers 264, side seal 260 can selectively resiliently deform along itsentire vertical extent to closely conform to each individual case 22and/or spacer 30 of pallet assembly 52, regardless of the non-uniformcorner surfaces which may be presented by these structures as shown inFIG. 16. In the illustrated embodiment, fibers 264 of seal 260 extendoutwardly away from plane P of airflow opening 54 (FIG. 13) in both thedepth direction (i.e., fibers 264 protrude inwardly into pallet bay 202)and in the width direction (i.e., fibers 264 protrude laterally awayfrom airflow opening 54). However, fibers 264 are each substantiallyparallel with the ground, and therefore do not extend vertically alongthe height direction by a substantial amount (e.g., each fiber 264protrudes vertically by less than 5% of its axial length). As best seenin FIG. 16, this configuration of fibers 264 takes advantage of thegenerally rectangular cuboid shape of cases 22 and spacers 30 such thatfibers 264 follow the right-angle contour of pallet assembly 52, tominimize air gaps between side seal 260 and unevenly stacked palletassembly 52.

In addition, the fibers 264 of seal 260 are arranged to collectivelypresent a substantially planar seal surface to the incoming corners ofpallet assembly 52, with the seal surface facing into the pallet bay 202as illustrated in FIG. 12. This substantially planar seal surfacedefines obtuse angle α with plane P, as shown in FIG. 13. In anexemplary embodiment, angle α is between 120 and 150 degrees. Whenpallet assembly 52 is received into and seated within bay 202, as shownby a comparison of FIGS. 13 and 14, this angular arrangement of the sealsurface ensures that seal 260 deforms both in a depth direction, i.e.,individual fibers 264 are urged deeper into bay 202 toward airflowopening 54 and chamber 6, as well as in a width direction, i.e., fibers264 are urged sideways laterally away from pallet bay 202 and opening54, as shown in FIG. 14. As noted above, left side seal 260 is a mirrorimage of right side seal 262 in the illustrated embodiment. Accordingly,the resiliently deformable seal surface formed by right side seal 262also defines obtuse angle α which, in an exemplary embodiment, isidentical to angle α defined by left side seal 260.

Although side seals 260, 262 are illustrated as resiliently deformable“brush seals” having seal fibers 264 as described above, it iscontemplated that other resiliently deformable materials may be used tocreate the angled seal surfaces for similar engagement with the left andright corners of pallet assembly 52. For example, it is contemplatedthat a suitable seal surface can be formed from a sheet of flexiblefabric, plastic or latex material stretched within a frame having thedesired periphery and orientation. In another alternative, a resilientlydeformable block of foam may be used, with the foam forming a sealingsurface of similar size, shape, and orientation as the sealing surfacesof seals 260, 262. Moreover, any material may be chosen to form thesealing surfaces of seals 260, 262, provided that the materials presenta “tangent” surface to the respective corners of pallet assembly 52which can deflect to fill or substantially fill respective gaps formedby unevenly stacked cases 22, as shown in FIG. 16. This “tangent”surface is generally contacted directly by the corners of palletassembly 52, such that the surfaces of individual cases 22 which formeach respective portion of the corners form an acute angle with theadjacent sealing surface 260 or 262. For a typical case 22 having acorner which forms a right angle as shown in FIG. 13, for example, theadjacent surfaces of the case 22 form angles equal to (α-90) degrees and(180-α) degrees respectively, both of which are acute angles where α isobtuse as noted above.

As noted above, swing seals 40 are used at the top portion of airflowopening 54 in order to seal the top inner corner of pallet assembly 52against the forward facing surface of swing seal 40 to prevent airleakage over the top of pallet assembly 52 and through the top portionof airflow opening 54 when pallet assembly 52 is shorter than opening54, as shown in FIG. 18. Additional details of an exemplary swing seal40 are disclosed in U.S. Pat. No. 8,919,142, filed Mar. 29, 2011 andentitled “Swing Seal for a Rack Aisle Freezing and Chilling System”, theentire disclosure of which is hereby explicitly incorporated byreferenced herein. When pallet assembly 52 is fully seated in pallet bay202 and pallet 4 is abutted against pallet stop frame member 238 asdescribed above, a seal is formed between the upper edge of palletassembly 52 and the adjacent seal surface 64 of swing seal 40 (FIG. 17).Swing seal 40 “automatically” adjusts to the height of pallet assembly52, by pivoting as far as needed into chamber 6 to maintain a tight andeven seal across the top inner edge of pallet assembly 52, asillustrated in FIGS. 6 and 18.

Turning now to FIG. 17, an exemplary embodiment of swing seal 40 isillustrated in cross-section, showing pivot point 60 which forms thehorizontal pivot axis of swing seal 40. Swing seal 40 is pivotablyconnected to bracket 62 at pivot point 60, and bracket 62 is connectedto vertical member 236 within bay 202. Thus, seal surface 64 of swingseal 40 sits proud of opening plane P and within bay 202 as illustrated.This configuration ensures that when pallet assembly 52 is fully seatedwithin pallet bay 202, seal surface 64 will reliably engage theuppermost row of cases 22 to form the desired seal, even if cases 22 areslightly misaligned, e.g., if the top row of cases 22 have shifted alongthe depth direction toward the opening of bay 202 and aisle 10.

In order to further ensure a substantially air tight sealing engagementbetween seal surface 64 and pallet assembly 52, weight 68 may bedisposed on the dished surface 66 opposite seal surface 64, andpositioned nominally rearwardly (i.e., toward chamber 6) of pivot point60 such that weight 68 creates a moment urging swing seal 40 to pivotinwardly toward pallet bay 202 as illustrated in FIG. 17. Thus, in theillustrated at-rest position, seal surface 64 is pivoted furtherinwardly toward pallet bay 202 in its at-rest orientation, as comparedto a substantially vertical at-rest orientation which would result fromusing swing seal 40 without weight 68. This inward pivot further ensuresfirm engagement of seal surface 64 with pallet assembly 52, as shown inFIG. 18. In an exemplary embodiment, swing seal 40 may be about 30inches in height and about 40 inches wide to accommodate a 40 inch widepallet as described above. In this size, weight 68 may be formed as abar extending across the lower portion of dished surface 66, having aweight of between 1 pound and 5 pounds and positioned between 1 inch and12 inches rearwardly of pivot point 60, where the “rearward” directionis taken to be a direction perpendicular to seal surface 64.

In an alternative embodiment shown in FIG. 17B, swing seal weightassembly 70 may be used in place of, or in addition to, weight 68 shownin FIG. 17A. As best seen in FIG. 17C, weight assembly 70 includes leftand right L-shaped pivot arms 72, 74 including a generally verticalportion which extends downwardly from pivot point 60, and a generallyhorizontal portion which extends rearwardly away from swing seal 40 intoplenum 6. Pivot arms 72, 74 are joined at the ends of therearwardly-extending portions by crossbar 76, and stop limit brackets 78are coupled to outer surfaces of each of pivot arms 72, 74. Pivotapertures 72A, 74A are formed near the respective ends of the verticalportions of pivot arms 72, 74, opposite crossbar 76, and serve as amounting point to pivotably attach weight assembly 70 to racking 14(e.g., to vertical members 236 of racking 14) as further describedbelow. Crossbar 76 further includes apertures 76A for affixation ofadditional weight to assembly 70, as needed. In an exemplary embodiment,assembly 70 is created from metal bar stock (e.g., steel) weldedtogether to form a unitary whole with significant mass.

Referring still to FIG. 17B, assembly 70 is pivotably attached tobrackets 62 at pivot points 60, via fasteners or a pivot axle passingthrough pivot apertures 72A and 74B on the left and right sidesrespectively (FIG. 17B is a cross-section showing the right-sideattachment point, it being understood that the left side attachment isthe same). Swing seal assembly 70 may be fixed to swing seal 40 at pivotpoints 60, such that swing seal 40 and weight assembly 70 rotatetogether as a single unit. Alternatively, weight assembly 70 may rotateindependently of swing seal 40, and may urge swing seal 40 into bay 202(as described below) by contact between brackets 78 and the edges ofdished surface 66, and/or by contact between pivot bars 72, 74 and theinner portion of dished surface 66.

In use, the rearwardly-extending portions of pivot arms 72, 74 andcrossbar 76 create a torque or moment about pivot point 60, such thatweight assembly 70 contacts the substantially vertical swing seal 40 andurges swing seal 40 into pallet bay 40. Similar to weight 68 describedabove, this biases swing seal 40 into contact with the upper portion ofthe cases on any pallet assembly 52 received within bay 202, therebyensuring a firm and effective seal therebetween. When bay 202 is vacant,however, limit stop brackets 78 are positioned to contact a portion ofracking 14, such as a lip or surface of vertical frame members 236 (FIG.17B), in order to prevent swing seal 40 from moving too far into thevacant bay 202 and creating an unnecessary vacant-bay airflow gap.Additional structures for preventing airflow through vacant bay 202 inthe area below swing seal 40 are further discussed herein.

The amount of biasing force provided by seal assembly 70 may be variedas required or desired for a particular application. As noted above,weights (not shown) may be fixed to apertures 76A to increase theeffective weight of crossbar 76, thereby increasing the moment appliedabout pivot point 60 and increasing the inward bias of swing seal 40into bay 202. In addition, the material and geometry of weight assembly70 may be modified as needed, with heavier materials and increasingrearward protrusion of pivot arms 72, 74 and crossbar 76 into plenum 6both contributing to increased biasing force. For top-row use in racking14, such rearward protrusion may be limited to avoid spatial conflictwith fans 12, which may protrude downwardly into plenum 6. Accordingly,weight increases may be favored over geometry reconfigurations forincreasing bias on swing seal 40 for top-row applications.

In a further alternative embodiment, swing seal 40 could be omittedentirely and a resiliently deformable seal of similar structure andarrangement to left and right side seals 260, 262 could be used alongthe top portion of the periphery of air flow opening 54. Such anarrangement would be appropriate, for example, where pallet assemblies52 are expected to have a fixed height which about equal to the heightof airflow opening 54.

As noted above, the provision of resiliently deformable side seals 260,262 and a suitable top seal arrangement, such as swing seal 40 or athird deformable seal, creates a substantially air tight interfacebetween pallet assembly 52 and airflow opening 54 even when palletassembly 52 does not have even, linear corners and sealing surfaces.This airtight arrangement, in cooperation with the structure and designof air chamber 6 which is also air tight at end walls 15 and top panel17, facilitates airflow driven by fans 212 almost entirely through theperforations in pallet assembly 52 (e.g., through air channels 38 formedin spacers 30, as shown in FIG. 9 and described above). Stated anotherway, the arrangement described above and shown in the drawings onlyrequires sufficient total airflow through chamber 6 to achieve thedesired function of thermal transfer between air within warehouse 2 andthe product contained in cases 22, with very little additional airflowrequired to compensate for leakage or other inefficiencies. In oneexample, 1,500 to 3,000 cubic feet per minute (CFM) of air may passthrough a typical pallet assembly 52 including spacers 30. Thus, for aset of ten pallet assemblies 52 served by a single fan 212, as little as15,000 cubic feet per minute of fan capacity may be sufficient.

In an exemplary embodiment, fans 212 (FIG. 11) may be direct-drive,axial propeller fans configured to produce two horsepower running a42-54 inch propeller at about 900 rpm. For purposes of the presentdisclosure a “direct drive” fan is a fan having a motor and a rotarymotor output with a longitudinal axis, in which the motor output iscoaxial with the rotary axis of the fan propeller, such as by having themotor output coupled directly to the propeller. This type of fan ishighly efficient as compared to non-direct-drive fans, such as fan 12shown in FIG. 8. Although fan 12 may of course be used in conjunctionwith racking assembly 214 as required or desired for a particularapplication, one or two direct drive fans 212 (such as two shown in FIG.11) may be used for each set of 8 pallet bays 202 (i.e., four rows oftwo). Propeller fans 212 also have a reduced height above top panel 17as compared to fan 12, which lowers the overall height of a givenracking arrangement and, in some applications, may enable an additionalrow of pallet bays 202 within a given warehouse 2.

In the illustrated embodiment of FIG. 11, additional end walls 15 may beused in the interior of chamber 6, in addition to end walls 15 at theterminal lateral ends of chamber 6. These interior walls 15 partitionchamber 6 into hermetically sealed units within racking assembly 214,creating airflow isolation between portions of air chamber 6. In thisconfiguration, fans 212 may be selectively powered or left idledepending on which parts of racking assembly 214 are in use at any onetime. In an exemplary embodiment, top panel 17 may include modular fanmounting tracks periodically arranged to coincide with each partitionedportion of chamber 6, with each set of mounting tracks sized to acceptone or two fans 212. As noted above, a single fan 212 having a 20,000CFM capacity may be sufficient to serve up to 8-10 bays 202 (i.e., 4-5rows of two bays 202), while a second fan 212 of the same capacityraises the upper limit to 16-20 bays 202 (i.e., 8-10 rows of two bays202). In shorter racking arrangements where only a single fan 212 isneeded, a plug panel may be mounted to the mounting tracks to enclosethe partitioned portion of chamber 6. In other embodiments, interiorwalls 15 may be placed in other locations to create rows of 1, 2, 3 or 4pallet bays 202 in each partitioned portion of chamber 6, with thenumber of fans 212 also ranging between 1 and 4 fans per partitionedportion as required or desired for a particular application. Moreover,the modular system described herein can be configured in any desiredarrangement of partitions, fan capacity, and overall rack width andheight as needed.

The use of relatively lower-power direct-drive axial fans 212 is enabledby the airtight arrangement of racking 214, such that two or even one 2horsepower direct drive fan 212 may be used for a set of 8 pallet bays202 as noted above. This represents a 20-60% efficiency improvement overconventional centrifugal fans 12. Stated another way, a reduced pressuredifferential within chamber 6 may be used in racking 214 while stillperforming sufficient heat transfer operations on pallet assemblies 52,as compared to predicate designs. In an exemplary embodiment, a pressuredifferential of 0.25 inches of water may be sufficient to draw a desiredamount of air through pallet assemblies 52 using racking 214, ascompared to up to in excess of 1 inch of water for high powercentrifugal fan arrangement. In one particular exemplary embodiment,0.375 inches of water has been found to be more than adequate for blastfreezing operations where fans 212 create a vacuum pressure differentialin chamber 6 as compared to the ambient pressure within warehouse 2,such that air is drawn through pallet assemblies 52 from the ambientvicinity (e.g., aisles 10 of FIG. 1) and into chamber 6 via airflowopenings 54.

As an alternative to fans 212 creating vacuum pressure within chamber 6as described above, it is contemplated that fans 212 may be reversed tocreate a relatively higher pressure in chamber 6 compared to the ambientenvironment, such that airflow is reversed through pallet assemblies 52.In this configuration, air is “pushed” through spacers 30 from airflowopening 54 toward the ambient environment of warehouse 2, rather thanbeing “drawn” through pallet assemblies 52 when fans 212 create a vacuumpressure within chamber 6. In the case where fans 212 blow into chamber6 to elevate the pressure therein, fans 212 form the inlet of theillustrated embodiment, and airflow openings 54 form the outlet.Conversely, where fans 212 blow outwardly to exhaust air from chamber 6,fans 212 are the outlet and airflow openings 54 are the inlets.

3. Vacant-Bay Compensation.

In addition to the above-described seal arrangement around the peripheryof airflow opening 54 and the modular partitioning of chamber 6,efficient heat-transfer operation of racking 214 may be accomplished byavoiding performance reductions when pallet assemblies 52 are removedfrom bays 202 to create one or more vacant bays 202 as illustrated inFIG. 10. In particular, racking 214 may avoid large flows of air throughairflow openings 54 when bays 202 are vacant by a baffle system, asdescribed in detail below, thereby avoiding the need to increase fancapacity to maintain desired air flows through pallet assemblies 52 inthe remaining occupied bays 202.

Turning now to FIGS. 18 and 19, a set of air dams 270 are illustrated indisengaged configurations (FIG. 18) and engaged configurations (FIG.19). Air dams 270 are provided to facilitate less than 100% occupancy(FIG. 10) in pallet bays 202 served by a fan or fans 212. In particular,and as described in further detail below, air dams 270 arrest theincreased airflow through airflow opening 54 when a pallet bay 202 isvacant (FIG. 19) as compared to such a pallet bay 202 being occupied bypallet assembly 52 (FIG. 18).

Referring specifically to FIG. 18, air dam 270 is pivotably mounted toair dam frame member 276 within chamber 6 via pivot connection 274. At alocation downstream of air dam 270, dam stop 272 is fixed to dam stopframe member 280 via a fixed connection, e.g. brackets 278. When thepallet bay 202 adjacent air dam 270 includes a pallet assembly 52sealingly engaged with opening 54, as illustrated, an operationalairflow passes through spacers 30 and into chamber 6 via airflow opening54. This operational airflow passes under and around air dam 270, and insome exemplary embodiments, air dam 270 itself may be perforated toallow a set amount of airflow directly through air dam 270 asillustrated. Accordingly, air dam 270 is configured to allow theoperational airflow to proceed unencumbered and therefore creates nosignificant impairment of the function of racking assembly 214.

Turning to FIG. 19, pallet bay 202 is shown vacant, with pallet assembly52 having been removed. In this configuration, the amount of airflowthrough the now-unobstructed airflow opening 54 experiences a brief butsignificant increase. For example, in one embodiment, airflow mayincrease between 50% to 100% from 2,000 to 3,000 cubic feet per minutethrough pallet assembly 52 with spacers 30, up to about 4,000 cubic feetper minute when pallet assembly 52 is removed. For pallet assemblies 52with predicate spacers 20, this increase may be even more drastic. Thisincreased airflow also increases the air pressure on air dam 270,causing it to pivot about pivot connection 274 and come into contactwith dam stop 272. At this point, airflow under air dam 270 is arrested.For solid air dams 270, no significant flow is permitted in thisconfiguration, while only a minimal amount of airflow through perforatedair dams 270 is permitted. Air dam 270 remains in its closed positionuntil pallet assembly 52 is loaded back into pallet bay 202, reducingthe local air pressure differential and allowing air dam 270 to pivotback to the disengaged configuration of FIG. 18 under its own weight.Air dam 270 reduces the airflow through the vacant bay 202, obviatingany need to increase the power or speed of fan 212 to compensate for theextra airflow while maintaining a desired pressure differential withinchamber 6.

In another embodiment, air dam 270 may be manually or automaticallycontrollable, such as by pneumatic cylinders with two way actuation.Such cylinders may pivot air dam 270 into the engaged configuration(FIG. 19) or the disengaged configuration (FIG. 18) based on theinstruction of an operator or electronic controller 282.

In addition, it is contemplated that controller 282 may be provided andoperably connected to fan 212 in order to control the pressuredifferential in airflow through chamber 6 depending on changingconditions, e.g., the number of vacant pallet bays 202 within a givenconfiguration of racking 214. For example, controller 282 may monitorpressure within chamber 6 with a transducer, and compare the measuredpressure with a desired set point or a range of set points. When themeasured pressure falls by a threshold amount, such as outside theacceptable pre-determined range of pressures, fan 212 may be sped up ora second fan 212 may be activated in order to bring the pressuredifferential back to a desired set point. Thus, when pallet assemblies52 are removed from bays 202 increasing airflow to chamber 6, fans 212may increase speed to compensate as long as necessary. For example, fan212 may speed up to induce actuation of air dam 270 as shown in FIG. 19,and then slow back down to a speed sufficient only to retain air dam 270in the desired closed configuration. In some configurations, air dam 270may be omitted and controller 282 may provide all of the necessaryincrease in air flow to compensate for vacant bays.

In the illustrated embodiment of FIGS. 18 and 19, air dams 270 areconfigured to pivot in a downstream air flow direction from bays 202toward chamber 6. Thus, the illustrated embodiment uses a vacuumpressure developed within chamber 6 by fans 212 exhausting to theambient air as described above. In an embodiment where higher pressureis developed in chamber 6 by fans 212 blowing into chamber 6, air dams270 will be arranged to pivot in the opposite direction as illustratedin FIGS. 18 and 19.

Air dams 270 may be provided in a variety of forms and configurations,as required or desired for a particular application. In one example, airdams 270 may be formed from a series of powered louvers or damperslocated inside the plenum space or chamber 6. Such louvers/dampers maybe individually pivotable and collectively linked to a single actuator,such that the plurality of louvers can be collectively actuated to blockor restrict airflow when a respective bay 202 is unoccupied. Suchlouvers may be provided in sufficient number and size to block orrestrict the air flow path for a single bay 202, or can be provided in alarger number and/or size to block or restrict airflow through a numberof bays 202 for certain applications.

In another embodiment, air dams 270 may be provided as an integrated“constant air volume” damper located inside the plenum space or chamber6, and includes one or more air flow-driven dampers which are arrangedand balanced to maintain a constant-volume air flow through opening 54regardless of whether bay 202 is occupied, unoccupied or partiallyoccupied. Additional details of a commercially available constant airvolume damper device is contained in Appendix A, entitled “CVQ ConstantAir Volume Damper”, forming a part of the present application, theentire disclosure of which is incorporated by reference herein. In anexemplary embodiment, such a constant air volume damper controls theairflow volume for a single bay 202.

As an alternative to the constant air volume damper described above, asimilar system may be provided with a damper designed to deliver avariable air volume. In this embodiment, the damper is located insidethe plenum space adjacent bay 202, similar to the embodiment describedabove. However, when bay 202 is unoccupied airflow volume throughopening 54 is significantly reduced as compared to the correspondingairflow volume when bay 202 is occupied by pallet assembly 52. In anexemplary embodiment, such a variable volume damper controls the airflowvolume for a single bay 202.

In yet another embodiment, a tilting panel of similar construction toair dam 270 (FIGS. 18 and 19) is provided with a “normally closed”configuration, i.e., air dam 270 is biased into an airflow-blockingconfiguration (similar to FIG. 19) by a biasing element such as gasstruts, springs or a spring-biased hinge. Air dam 270 is pushed to anopen configuration (similar to the configuration shown in FIG. 18) whena pallet assembly 52 is installed into the adjacent bay 202. Inparticular, when pallet assembly 52 is loaded into bay 202, palletassembly 52 engages a portion of the air dam 270 and physically pushesair dam 270 against the closing force of the biasing element. This tiltsthe panel into an open configuration in which air is allowed to flowfreely through opening 54.

In yet another embodiment, a door (similar to air dam 270) may bepivoted about a vertical axis with a hinge positioned at either the leftor right of opening 54. When the adjacent bay 202 is unoccupied, thedoor is swung closed either manually or automatically, e.g., with a dooractuator controllable by a switch and/or electronic controller. The doormay be positioned inside chamber 6, swinging outwardly away from opening54 into chamber 6, or may be positioned outside chamber 6 and within bay202, swinging inwardly into bay 202. If the door swings inwardly,actuation must occur when bay 202 is unoccupied.

In still another embodiment, a roll-up style door may be provided withinchamber 6 (i.e., on the chamber side of opening 54) or external tochamber 6 (i.e., on the bay side of opening 54). The roll-up style dooris rolled down to cover opening 54 when bay 202 is unoccupied, androlled up to allow airflow through opening 54 when bay 202 is occupied.

For any of the above-described structures for selectively blocking orallowing airflow through opening 54, an auxiliary opening may beprovided within chamber 6 and spaced away from opening 54. Thisauxiliary opening may take the form of a sheet metal box attached to thechamber side of wall 230, such that the sheet metal fluidly isolates theinterior of the box from chamber 6 except through the auxiliary opening.The auxiliary opening is positioned to generally align with opening 54,such that air may flow through both opening 54 and the auxiliary openingas it moves between bay 202 and chamber 6. The auxiliary opening may beselectively blocked in order to selectively interrupt such airflow asdescribed above, rather than directly blocking opening 54. The interiorspace of the box shifts the selectively blocked airflow opening awayfrom bay 202 and into chamber 6, thereby providing a physical space andvolume to accommodate various air blocking structure designs.

While this disclosure has been described as having exemplary designs,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the disclosure using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains and which fallwithin the limits of the appended claims.

1-24. (canceled)
 25. An installation for warehousing palletized product,comprising: a pallet assembly comprising: a pallet; and a plurality ofvertically stacked rows of cases disposed on the pallet and providing anairflow pathway through the vertically stacked rows of cases containingthe product; and a pallet racking assembly comprising: a palletreceiving space sized and configured to receive the pallet assembly; anairflow chamber including an air inlet and an air outlet; an air handlerconfigured and positioned to direct air into the airflow chamber fromthe air inlet and exhaust air from the airflow chamber through the airoutlet; a wall disposed between the pallet receiving space and theairflow chamber, the wall having an airflow opening sized and positionedto be engaged by the pallet assembly when the pallet assembly isreceived within the pallet receiving space, the airflow opening definingan unobstructed airflow when the pallet assembly is absent from thepallet receiving space and an operational airflow when the airflowopening is engaged by the pallet assembly, the operational airflow lessthan the unobstructed airflow; and an air dam positioned adjacent theairflow opening and configured to at least partially obstruct theairflow opening, the air dam and the airflow opening cooperating todefine a vacant-bay airflow when the pallet assembly is absent from thepallet receiving space, the vacant-bay airflow less than theunobstructed airflow.
 26. The installation of claim 25, wherein the airdam comprises a plurality of openings therethrough, the plurality ofopenings sized to provide the partial obstruction of the airflow openingwhile allowing the operational airflow to pass therethrough.
 27. Theinstallation of claim 25, wherein the air dam is movable between adisengaged configuration and an engaged configuration, the engagedconfiguration creating the partial obstruction of the airflow opening todefine the vacant-bay airflow, and the disengaged configuration definingreduced obstruction of the airflow opening as compared to the partialobstruction, such that the disengaged configuration of the air damcooperates with the airflow opening to define an occupied-bay airflowcommensurate with the operational airflow, whereby the air dam does notimpede airflow through the pallet assembly when in the disengagedconfiguration.
 28. The installation of claim 27, further comprising anair dam frame member disposed within the airflow chamber, the air dampivotably mounted to the air dam frame and pivotable between the engagedconfiguration and the disengaged configuration.
 29. The installation ofclaim 28, further comprising a dam stop fixed within the airflowchamber, the dam stop positioned to be engaged by the air dam when theair dam is in its disengaged configuration.
 30. The installation ofclaim 28, wherein the air dam is a solid air dam lacking aperturestherethrough, whereby the vacant-bay airflow is about zero.
 31. Theinstallation of claim 28, wherein the air dam is a perforated air damhaving apertures therethrough, whereby the vacant-bay airflow is abovezero.
 32. The installation of claim 27, wherein the air dam is actuatedby air flow, such that an increase in airflow through the airflowopening urges the air dam toward the engaged configuration.
 33. Theinstallation of claim 25, wherein: the pallet racking assembly comprisesa plurality of the pallet receiving spaces arranged in vertically spacedhorizontal rows; the wall includes a plurality of the airflow openingsrespectively disposed at each of the plurality of the pallet receivingspaces, whereby the pallet racking assembly is configured to accommodatea plurality of pallet assemblies, each of the airflow openings definingthe unobstructed airflow when a respective pallet assembly is absentfrom the respective pallet receiving space and the operational airflowwhen the respective airflow opening is engaged by the respective palletassembly; and each of the plurality of the airflow openings includes theair dam positioned adjacent thereto and cooperating with the respectiveairflow opening to define the vacant-bay airflow.
 34. The installationof claim 33, wherein the air handler defines an airflow output capacityless than the aggregated unobstructed airflow of the plurality ofairflow openings but at least as much as the aggregated operationalairflow and vacant-bay airflow of the plurality of airflow openings,whereby the air handler for the pallet racking assembly has a reducedcapacity as compared to a racking system lacking the air dams.
 35. Theinstallation of claim 25, wherein the unobstructed airflow is between50% to 100% greater than the operational airflow.
 36. The installationof claim 25, wherein the pallet assembly includes at least one spacerdisposed between the plurality of vertically stacked rows of cases, thespacer having a longitudinal airflow channel formed therethrough, thespacer cooperating with the plurality of vertically stacked rows ofcases and the airflow opening to define the operational airflow.
 37. Theinstallation of claim 36, wherein the operational airflow is between2,000 to 3,000 cubic feet per minute.
 38. The installation of claim 37,wherein the unobstructed airflow is about 4,000 cubic feet per minute.39. The installation of claim 25, further comprising: a controlleroperably connected to the air handler, a pressure transducer configuredto measure a pressure within the air chamber, the pressure transduceroperably connected to the controller; the controller programmed tocompare the measured pressure with a threshold and operate the airhandler to maintain the measured pressure within an acceptablepre-determined range of pressures.
 40. The installation of claim 39,wherein the air dam is movable between a disengaged configuration and anengaged configuration, the engaged configuration creating the partialobstruction of the airflow opening to define the vacant-bay airflow, andthe disengaged configuration defining reduced obstruction of the airflowopening as compared to the partial obstruction, such that the disengagedconfiguration of the air dam cooperates with the airflow opening todefine an occupied-bay airflow commensurate with the operationalairflow, whereby the air dam does not impede airflow through the palletassembly when in the disengaged configuration, the installation furthercomprising: an actuator connected to the air dam, the controlleroperably connected to the actuator and programmed to move the air daminto the engaged configuration when the pallet assembly is absent fromthe pallet receiving space and the disengaged configuration when theairflow opening is engaged by the pallet assembly.
 41. A method ofoperating an installation for warehousing palletized product, theinstallation including a pallet racking assembly including a palletreceiving space sized and configured to receive a pallet assembly, anairflow chamber including an air inlet and an air outlet, an air handlerconfigured and positioned to direct air into the airflow chamber fromthe air inlet and exhaust air from the airflow chamber through the airoutlet, and a wall disposed between the pallet receiving space and theairflow chamber, the wall having an airflow opening, the methodcomprising: activating the air handler to create a pressure differentialbetween the airflow chamber and the pallet receiving space, the pressuredifferential creating a vacant-bay airflow passing an air dam adjacentthe pallet receiving space, the vacant-bay airflow less than anunobstructed airflow that would be defined by the airflow opening alonegiven the pressure differential; and loading a pallet assembly into thepallet receiving space such that the pallet assembly occupies the palletreceiving space and blocks the airflow opening, the pressuredifferential creating an operational airflow through the palletassembly, through the airflow opening and passing the air dam, theoperational airflow less than the unobstructed airflow.
 42. The methodof claim 41, further comprising leaving a second pallet receiving spacevacant such that the pressure differential creates an operationalairflow through the occupied pallet receiving space and a vacant-bayairflow through the vacant pallet receiving space.
 43. The method ofclaim 42, wherein the vacant-bay airflow through the vacant palletreceiving space is less than the operational airflow through theoccupied pallet receiving space.
 44. The method of claim 40, furthercomprising moving the air dam from a disengaged configuration to anengaged configuration during the step of loading the pallet assembly.45. The method of claim 44, wherein the step of moving the air damcomprises pivoting the air dam within the airflow chamber.
 46. Themethod of claim 44, wherein the step of moving the air dam is effectedby the pressure differential.
 47. The method of claim 42, wherein thestep of moving the air dam is effected by an actuator coupled to the airdam and controlled by a controller.
 48. The method of claim 42, furthercomprising controlling a speed of the air handler to maintain thepressure differential within a predetermined range.